Here in the USA there are lot about of people that would rather swim in a ponds/lake and rivers. But that arnt the type you out and about. Or going out east for vacation.

In Germany and Austria, jumping in lakes for a swim is definitely a beloved (normal) summer activity. Skinny dipping, swimming naked is also popular (normal occurance) on hot days. (This is sometimes shocking to foreign visitors) Lakes and rivers near the glaciers in the alps are the clearest, with crystal blue limestone water. Further north towards the sea, people will swim only in lakes and don't usually swim in rivers, as they are polluted more heavily running through cities and being used as transportations.